Fuel injection apparatus for internal combustion engines



March 15, 1966 GRATZMULLER 3,240,192

FUEL INJECTION APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed Dec. 13, 1963 4 Sheets-Sheet 1 FIG/l 9 YIIIIIIIIIIIA ran III/IA I March 15, 1966 J. 1.. GRATZMULLER 3,240,192

FUEL INJECTION APPARATUS FOR INTERNAL COMBUSTION ENGINES 4 Sheets-Sheet 2 Filed Dec. 13, 1963 FIGS FIG. 6

Mflmh 1966 J. L. GRATZMULLER 3,240,192

FUEL INJECTION APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed Dec. 15, 1965 4 Sheets-Sheet 5 s n w I II I. F n B n M fl M a l 7 3|?! z u a. n 6 m .ID M w ws/ 6 1 9 7 2 a h 7 8 u M II, 211! l on A m m 4 o u 0 2% I I]: l I i f M f B N March 15, 1966 J. GRATZMULLER 3,240,192

FUEL INJECTION APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed Dec. 13, 1963 4 Sheets-Sheet a.

FIGS

United States Patent 3,240,192 FUEL INJECTION APPARATUS FOR INTERNAL COMBUSTION ENGINES Jean Louis Gratzmuller, 6d Blvd. Maurice Barres, Neuiily-snr-Seine, France Filed Dec. 13, 1963, Ser. No. 330,379 Claims priority, application France, Dec. 20, 1962, 919,250 12 Claims. (Cl. 12332) This invention relates to fuel injection techniques used in supplying fuel to the cylinders of internal combustion engines, and to apparatus for carrying such techniques into practice.

With certain types of internal combustion engines, and particularly Diesel engines, it is desirable to inject an accurately metered quantity of fuel into the engine cylinders, i.e., a quantity which is pre-set relative to the oxygen content of the air contained within each engine cylinder to which the fuel is supplied. Furthermore, it is desirable that an injection technique be used which insures random dispersal of the fuel within such air to effect most efficient combustion. Even further, it is important that the injection commence at a fixed time with respect to the cycle of operation of the engine, and in turn, the cylinder into which the injection is made. Additionally, it is known to be desirable to have a substantially constant pressure throughout the entire injection period since this readily permits a controlled injection of fuel.

Bearing in mind the foregoing, it will be understood that the basic considerations involve (a) precise timing control of the initiation of the fuel injection operation, and (b) maintenance of constant pressure throughout the injection period. Auxiliary to these considerations are the accurate metering and proper mixing aspects.

The instant invention is directed to efiicient yet simple techniques, and efficient yet simple apparatus, for accurately controlling the initiation of a fuel injection operation and for maintaining constant pressures during such operation, which techniques and apparatus further provide for, and readily permit, accurate metering of the fuel injected during an injection operation, and proper mixing of the fuel injected with the air in the chamber receiving the injection.

To fully appreciate the invention, it is necessary to comprehend the time characteristics of internal combustion engines to which fuel injection techniques can be advantageously applied. It has been found that the injection of fuel in an internal combustion engine properly takes place over a substantially minor part of the cycle of the engine. For example, in a four-cycle engine, the proper injection period for any given cylinder exists during a 20 displacement or rotation of the engine crankshafti.e., a 20 crankshaft displacement corresponds to the injection period of a given cylinder, and the remaining 700 (two rotations) of the cycle corresponds to a dwell or dead period insofar as the injection period for that cylinder is concerned. Translated into fractions, the injection lasts 9 of the cycle or A of the cycle.

Consistent with the above discussion, the importance of instantaneous injection initiation in a Diesel engine, for example, can readily be understood by considering a four-cycle engine operating at 1500 rpm. In such engine, the total duration of the injection period for any given one of the cylinders during any given cycle of operation is of the order of 14 of a second. Within this very short time period, the injection must take place and any control system causing the injection must operate to permit the injection. The control, as known, should be carried out in synchronism with operation of the engine. To this end, the crankshaft, for example, can be used to provide the initiating movement. Yet, the injection takes place at the top of the cylinders, and there is substantial distance between the crankshaft and the top of the cylinders.

The delays such as inherently experienced with conventional mechanical controls linked over such distance cannot be tolerated with short critical times of the order in question. Moreover, with mechanical arrangements, operating temperatures and time irregularities present themselves even with precision equipment, and for this additional reason, conventional mechanical control arrangements are not suitable for use as injection initiation controls.

Previously suggested hydraulic controls are also subject to inaccuracies. Specifically, where the injection is controlled through the application of pressure to the controlling means, there is an inherent delay of the order of of a second by virtue of the inherent hydraulic problems. While this delay appears small in magnitude, the same is large when compared with the small injection period experiencedi.e., injection periods of the order of $5 of a second. A similar situation exists where electrical controls are use. Here, current delays are encountered in operating solenoids, for example.

As indicated above, the primary object of the present invention is to provide a method of controlling fuel injection in an internal combustion engine, which method is not subject to the aforesaid disadvantages, and which method insures precise timing of the injection operation. To this end, it is a specific object of the present invention to provide such a method wherein the injection operation is initiated through a lowering or diminishing of hydraulic pressure used for injection control, whereby the response of the control is instantaneousi.e., extremely small when compared to even the small total injection times encountered.

Consistent with the above objects, it is a further primary object hereof to provide such a method wherein pressure is applied to the controls associated wit-h each cylinder of the engine to permit the filling of a fuel storage chamber for the cylinder during the non-injection phase thereof, and wherein the pressure is diminished during the injection phase to cause injection of the fuel from the storage chamber to the particular cylinder associated therewith.

Still further, it is a significant object hereof to provide such a method wherein the timing of the injection and non-injection steps are performed in synchronism with the operation of the engine itself, and specifically wherein the steps of the method are timed in accordance with operation of an available timing source such as the engine crankshaft.

By utilizing an engine synchronized series of steps and by utilizing a pressure decrease to initiate the injection step itself, accurate timing of the injection operation is achieved. Specifically, a decrease in pressure permits an instantaneous response free of problems which are attendant to operations controlled by pressure increases, e.g., vibration and compression problems. The advantage afforded by the invention in this regard is particularly significant, and can possibly be better understood again by way of example. Where a mechanical operation such as the opening of a valve is to be achieved by pressurizing a hydraulic circuit, one faces the problem of first obtaining the pressure, of then compressing any entrapped gas in the hydraulic system, and of then achievving the mechanical movement. With a pressure decrease, the mechanical movement is comparatively instantaneous since no energy need be used to lower the pressure and since other problems, such as gas entrapment problems are eliminated.

In accordance with the invention, the dwell or dead period which constitutes of the cycle is used for metering the fuel and obtaining the necessary energy to effect the desired injection. Specifically, in accordance with the method hereof, separate storage chambers are individually associated and separately coupled with each of the cylinders of the engine. The coupling is effected or controlled by hydraulically responsive control means associated with each of the storage chamber-cylinder subsystems. The cylinders, as conventional, operate with respective cyclically repeating injection and non-injection phasesthe injection phase as indicated above, being a minor fractional part of the overall cycle for both phases.

Following the method hereof, a metered quantity of fuel under pressure is accumulated in the storage chamber associated with each cylinder during at least a portion of the non-injection phase thereof. Also, during such phase, the hydraulically responsive control means associated with the cylinder assumes an operative condition resulting from the application of fluid under pressure, which prevents fluid transfer between the cylinder and the storage means coupled thereto. In other words, by applying hydraulic pressure, fluid flow is shut-ofif between each cylinder and its associated storage chamber during the non-injection phase of the cylinder.

To effect the injection, the pressure on the control fluid is diminishedi.e., the pressure is lowered and preferably removed from the fluid which previously was acting on the control means. Consistent herewith, the control means then instantaneously establishes communication between the storage chamber and the cylinder, thus resulting in the injection into the cylinder of the fuel under pressure.

Apart from the method aspects hereof, the invention has certain more important apparatus aspects. In particular, it is an object hereof to provide an apparatus for carrying out the aforesaid methods, which apparatus includes storage chamber means individually and separately associated and coupled with each of the engine cylinders, hydraulically responsive means for establishing and disestablishing communication between the respective cylinders and their individually associated storage means, and hydraulic circuit means coupled with the control means and adapted to be operated from a convenient timing source such as the engine crankcase so as to instantaneously establish communication between any given chamber and its associated cylinder when an injection operation is indicated, and yet so as to disestablish such communication at required periods. Additionally, it is an important olbject hereof to provide such an apparatus wherein the control means is responsive to a decrease in applied pressure to achieve the instantaneous establishment of communication between the storage chamber and the particular cylinder associated therewith.

In line with the preceding objects, further significant apparatus objects hereof include: (a) the provision of such an apparatus wherein each storage chamber means thereof is so constructed as to effectively meter the quantity of fuel delivered to its associated cylinder during an injection operation; (b) the provision of such an apparatus wheren each storage chamber means is so constructed that it provides substantially constant pressure on the fuel being injected therefrom during the injection operation; (c) the provision of such an apparatus wherein fuel under pressure is not only fed to the storage chamber means but additionally serves as the hydraulic fluid for controlling the injection operation or specifically the operation of the system control means; (d) the provision of such an apparatus which is responsive to the application of pressure on hydraulic fluid fed to the control means thereof to shut off communication between a given storage means and its associated cylinder during a chamber filling operation, and yet also responsive to a decrease in such pressure to establish the communication between the chamber and its associated cylinder whereby the injection is effected instantaneously as required, and whereby the delays encountered by pressure application through the control system take place during the long dwell or dead periods so as to not adversely afiect system operation.

The invention lies in methods of fuel injection and in apparatus combinations and arrangements for carrying out the methods. The invention will be better understood, and objects other than those set forth above will become apparent, when consideration is given to the following detailed description. Such description refers to the annexed drawings presenting preferred and illustrative embodiments of the invention.

In the drawings:

FIGURE 1 is a schematic diagram of a fuel injection system constructed in accordance with the present invention, such system operating in accordance with one embodiment hereof wherein the system hydraulic control circuit is independent of the system fuel supply circuit;

FIGURE 2 is a schematic diagram of a modified fuel injection system constructed in accordance herewith wherein the fuel itself is used as the fluid in the system control circuit;

FIGURE 3 is a schematic diagram of a further modified form of fuel injection system constructed in accordance herewith wherein the injection is controlled in accordance with fuel supply pressure and using the fuel itself in the system control means;

FIGURE 4 is a fragmental sectional view of a storage chamber means constructed in accordance herewith and having therein control valve means and metering means operated in accordance with the invention;

FIGURE 5 is a fragmental sectional view of a modified metering means adapted to be used in a storage chamber means constructed in accordance herewith;

FIGURE 6 is a fragmental view, partially in section and partially schematic, showing a further modified storrage chamber means constructed in accordance herewith and particularly adapted to be used advantageously in the system of FIGURE 3; and,

FIGURE 7 is a longitudinal sectional view of a preferred form of storage chamber means constructed in accordance herewith.

FIGURE 8 is a general schematic diagram of an overall system constructed in accordance herewith and associated with a plurality of cylinders of an internal combustion engine.

Although the invention is applicable to the injection of fuel in each cylinder of an internal combustion engine, the injection sequence and control is essentially the same for each cylinder and thus FIGURE 1 presents the system hereof as associated with a single cylinder of an internal combustion engine. Such cylinder is designated by the numeral 2, and as conventional, has a piston 44 reciprocal therein. Piston 44 is coupled with a rod 44a which leads to the engine drive shaft (not shown). The cylinder 2 is fed with fuel through an injection tube or nozzle 12 which leads from a fuel storage means S particularly associated with the cylinder 2. The storage means S, as shown, has a chamber '30 therein, and a piston 28 is reciprocally movable in the chamber 30. Such piston carries a depending valve member or arm 14 which is adapted to seat on the upper end of the injection tube 12 to close off fluid communication between the storage means S and the cylinder 2.

The method of the invention contemplates operating such an arrangement whereby fuel is injected into the cylinder 2 above the piston 44 at a given time, i.e., during the injection phase of cylinder 2, and whereby the storage means 8 accumulates a metered quantity of fuel therein during the non-injection phase of the cylinder 2. It will be remembered from the above discussion that each cylinder of the internal combustion engine has both an injection phase and a non-injection phase. During the injection phase, fuel is injected through the tube 12 into the cylinder 2, whereas during the non-injection phase, no, fuel is injected into the chamber.

Consistent with such method aspects, the'system of FIGURE 1 includes a fuel line 16 which leads into the chamber 4 of the storage means S through a one-way nonreturn valve 26. This fuel line is supplied with fuel under pressure, such fuel being transferred from the fuel reservoir 22 to a conventional hydropneumatic reservoir 18 via a conventional auto-regulating pump 20. A control valve 24 is coupled in the line 16 between the hydropneumatic reservoir 18 and the chamber 4 of the storage means S.

The valve 24 is controlled by any suitable means such as, for example, a cam (not shown) which is coupled to the engine crank shaft to sychronize the operation of the valve 24 with the normal cycles of operation of the engine. The valve 24, according to the invention, only opens the line from the reservoir 18 to the chamber 4 during the non-injection phase of operation of the cylinder 2. During the injection phase, the valve 24 closes the line 16 so that the chamber 4 does not communicate with the reservoir 18.

With the above system, and the operation described, fuel is supplied to the chamber 4 of the storage means S during at least a portion of the non-injection phase of such cylinder. As the fuel is supplied to the chamber 4, the chamber 4 essentially expands. To this end, it will be noted that the storage means S or more specifically the chamber 4 therein has an auxiliary branch 4a in which a piston 6 is reciprocally movable. The piston 6 is normally biased inwardly of branch 4a toward the main chamber 4 by a biasing means which, as shown, takes the form of a spring 8. The spring 8 is supported in a suitable frame 8a whereby the piston 6 can react against such spring moving to the left as shown in the branch 40 thereby increasing the effective capacity of the storage chamber 4.

In fact, when fuel under pressure is supplied through the line 16, it serves to move the piston 6 rearwardly or to the left in the chamber 4a thereby compressing the spring 8. The movement of the piston 6 is controlled by the compressibility of the spring 8 and the movement of the piston 6 permits the metering of a given quantity of fuel determined by the timed operation of valve 24, as explained more fully below.

During the non-injection phase of the cylinder 2, and while a metered quantity of fuel under pressure is accumulated in the storage means S, the piston 28 therein is being urged downwardly whereby the valve member 14 closes the injection tube 12. Specifically, hydraulic fluid under pressure is supplied through the line 32 to the chamber 30 to urge the piston 28 downwardly, and this application of hydraulic fluid under pressure serves to maintain the injection tube or nozzle 12 closed. The valve member 14 and injection tube 12 can properly be considered as a hydraulically responsive outlet means associated with the storage means S, and consistent with this terminology, the outlet means is, through the application of hydraulic fluid under pressure maintained in operative condition to prevent fluid transfer between the cylinder 2 and the storage means S coupled thereto at least during the filling of the storage means S with fuel and immediately prior to the start of the injection phase.

The line 32 is part of a hydraulic control circuit which further includes a three-way valve 40, a hydropneumatic reservoir 34, and an auxiliary reservoir or sump 38. The reservoir 34 is charged by a pump 36 which is coupled in a iine 36a leading from the sump 38 to the reservoir or accumulator 34. When the valve 4-0 is rotated from the position shown in FIGURE 1 to the position where it couples the line 34a leading from the accumulator 34 with the line 32, hydraulic fluid under pressure is applied to the top of the piston 28 thereby effecting the condition described immediately above.

When, however, the valve 40 is rotated to the position shown in FIGURE 1, then the line 32 is connected with the sump 38, and the pressure is removed from the top of the piston 28. Consistent herewith, the valve 40 is operated by suitable means such as a cam (not shown) carried on the engine crank shaft so that the valve 40 assumes the position shown in FIGURE 1 when the injection phase of the cylinder 2 is to be initiated and so that the valve 40 communicates the line 32 with the line 34a during at least a portion of the non-injection phase of the cylinder 2.

Assume that the chamber 4 and the branch 4a have fuel under pressure accumulated therein by virtue of the supply of fuel through the line 16 as described above. Assume further that the valve 24 has been moved to its closed position. Assume further that the valve 40 is moved to the position shown by virtue of its coupling, for example, with the crank shaft. At this time, the previously existent pressure in the chamber 30 is removed. This diminishing of the pressure is achieved instantaneously, i.e., the pressure drop is transmitted at the speed of sound. Instantaneously, the fuel under pressure in the chamber 4 and branch 4a exerts its force on the lower face of the piston 28 thereby moving the same immediately upward from the position shown and in turn, opening the injection tube or nozzle 12 by virtue of the consequent lifting of the valve member 14. Under the action of the spring 8, the piston 6 moves to the right as shown, and fuel is forced through the injection tube 12 under a substantially constant pressure maintained by the spring 8 biasing the piston 6 to the right. It should here be noted that the removal of pressure in the chamber 30 permits instantaneous action since it is not dependent on shock vibrations, gas compression, or the like. Moreover, the action of the piston 6 is instantaneous and thus there is an instantaneous discharge of fuel through the injection tube 12 when the valve 40 is moved to the position shown in FIGURE 1. The

" amount of fuel dispensed through the injection tube 12 is controlled or metered depending upon the timing of valve 24, i.e., the time of fuel supply through line 16. There is thus the desired accurate metering and instantaneous injection initiation. It will be readily appreciated that the injection tube or nozzle 12 can have a conventional dispersing outlet to insure proper mixing and that the fuel is maintained under substantially constant injection pressure by the piston 6.

Following the injection described above, the valve 40 moves to its other position communicating the line 34a with the line 32. At this time, the piston 28 is moved downwardly to its initial position by virtue of the pressure exerted thereon by the fluid supplied to the chamber 30. The fact that some delay might be encountered in moving the piston 28 downwardly and thereby in closing the injection tube 12 with the valve member 14 makes little difference because the time of termination of the injection is not critical and instead, as explained above, the time of initiation of the injection is the critical factor.

The time of operation of the valve 24 in the fuel line 16 is important because in this instance it controls the metering. The operation of the valve 40 is important from the time standpoint, but this valve, like valve 24, can be located adjacent the crank shaft so as to minimize any time delays in operation. The distance between such valve and the storage means S makes little difference since the operation of the valve 40 at the critical injection time-i.e., at the start of the injection operation, effects a lowering of the pressure in the line 32 which in turn permits instantaneous response from the piston 28.

To those familiar with the art, it will be understood that valve 40 can easily be a rotary valve that it is controlled in synchronization with the motor crank shaft by means of gears, cams, or the like (not shown). It will further be understood that the system of FIGURE 1 can be used with each of the cylinders in an internal combustion engine. To this end, each cylinder would have its own storage means S and its own hydraulic control circuit. The hydropneumatic reservoir or accumulator 18 need not be repeated for each cylinder since they can be commonly connected to all of the storage means through respective valves 24.

It is important to note that the end of the injection operation is not fixed by closing of the induction tube 12 by the valve member 14. Instead, the termination of the injection is fixed by the reduction in the total amount of fuel expelled from the chamber 4--the storage means being so arranged that the induction tube 12 only receives fuel from the chamber 4 during movement of the piston 6 to its extreme inner position.

The system of FIGURE 2 operates basically in the identical manner as the system of FIGURE 1, but here the hydraulic fluid which controls the movement of the piston 28 constitutes the fuel itself. Insofar as the storage means S is concerned, and insofar as the valve 26, line 16, valve 24, accumulator 18, pump 20, and reservoir 22 are concerned, the system of FIGURE 2 is: identical with the system of FIGURE 1. In the control circuit of FIG- URE 2, the arrangement differs however.

Specifically, by referring to FIGURE 2, it will be noted that a branch line 48 leads from the fuel line 16 of FIG- URE 2 and such branch line feeds through a one-way non-return valve 46 to the line 32, and in turn to the chamber 30 for piston 28. The line 32 is itself coupled by return line 42 to the reservoir 22 through a one-way valve 40' interposed in the line 32-42. During at least a part of' the normal non-injection phase of the cylinder 2 of FIGURE 2, the valve 24 is open and fuel under pressure feeds from the accumulator 18 through the line 16 and the branch line 48 into the line 32 and in turn into the chamber 30. The one-way valve 40 is closed at this time. The one-way valve 26 is constructed to have a slightly greater operation time than the one-way valve 46 and thus the fuel exerts its pressure on the piston 28 before the same enters the chamber 4. Accordingly, during the filling of storage means S the valve member 14 is maintained in blocking or closing relation to the induction tube 12. The chamber 4 and the branch 4a consequently fill with fluidthe piston 6 moving outwardly as explained in connection with FIGURE 1.

At the time the injection operation is to be initiated, the cam 50 operated, for example, with rotation of the crank shaft, opens the one-way valve 40' thereby establishing return to the reservoir 22 from the line 32 through the line 42. The pressure of the fluid in the chamber 30 is diminished and the injection operation is initiated just as described above, with the pressure change being transmitted at the speed of sound.

With the arrangement of FIGURE 2, however, no auxiliary hydraulic fluid is required, and instead, the fuel itself is used for the hydraulic control. In this instance, the one-way valve 26 prevents expulsion of fuel from the chamber 4 through the inlet, just as it did in the system of FIGURE 1. The one-way valve 46 prevents a coupling of the line 32 with the line 16 thereby preventing any tendency of fuel return from the line 32 to the line 16.

In the arrangement of FIGURES 1 and 2, the quantity of fuel to be dispensed from the storage means S is controlled by the quantity of fuel fed thereto. Accordingly, the fuel is metered by the time during which the valve 24 remains open. In contrast, the arrangement of FIGURE 3 provides a different type of fuel metering. Still further, the arrangement of FIGURE 3 provides for controlling the injection timing by the fuel supply pressure itself. It should here be noted that the cyclic variation in fuel supply pressure to be discussed can be caused in various different ways, as for example, by a pump having a controlled supply. Still, the system of FIGURE 3 is a preferred arrangement.

By referring to FIGURE 3, it will be noted that the storage means S shown therein is essentially the same as the storage means used in FIGURES 1 and 2. The line 32 of FIGURE 3, however, leads directly into the line 16 on the supply side of the one-way valve 26. With such an arrangement, when fluid under pressure is supplied to 5% the line 16, the same exerts its pressure on the piston 28 thereby causing the valve member 14 to block the opening through the injection tube or nozzle 12. At the same time, fuel is introduced into the chamber 4 and the branch 4a thereof causing outward movement of the piston 6 as described above.

In this type of system, when pressure is removed from the fuel in the line 16, the piston 28 can move upwardly due to the diminished pressure in the chamber 30. Still, the fuel within the chamber 4 and its branch 4a in excess of the standard reserve quantity is injected under the action of the piston 6, and upon the upward movement of the valve member 14 resulting from the lowering 0f the pressure in the chamber 30.

While as indicated the variation in the fuel supply pressure may be achieved in various ways, as for example through the use of an uninterrupted supply pump, such variation is preferably obtained from a fuel supply means such as that shown in FIGURE 3, and generally designated by the letter F. This fuel supply means includes a piston pump 52 which is reciprocated by a cam 54 attached, for example, to the crank shaft of the engine. The pump 52 discharges fuel, upon upward reciprocation of the piston thereof, into a supply line 56, the pump receiving its fuel from the line 22a leading from the fuel reservoir 22. A one-way non-return valve 58 is interposed in the line 56 which couples with the line 16 through a chamber 60a. The chamber 60a is coupled with the supply reservoir 22 by a tube 62, which tube is cl-osable by the valve member 6% extending upwardly from the piston 60. The piston 60 is reciprocal in the chamber 60a and is normally biased upwardly by a spring 60c to cause the valve member 60b to block the tube 62.

When the piston of piston pump 52 is moved upwardly with rotation of the cam 54, it moves the fuel disposed above the face thereof into the line 56 as well as into the line 64 coupled in parallel therewith. Simultaneously, the line 22a is shut-off. The fuel moving into the line 64 immediately urges the piston 60 upwardly thereby adding this effect to spring 600 to block the outlet of the tube 62. At the same time, fuel is forced through the line 56, the one-way valve 58, and the chamber 6011 into the line 16. The quantity of fuel so moved is dependent upon the stroke of the piston pump 52. The pressure on the fuel so moved serves to force the piston 28 downwardly. Moreover, the fuel is introduced into the chamber 4 thereby charging the same.

With the system of FIGURE 3, fuel is accumulated in the storage means S immediately preceding the injection phase of the cylinder 2, such accumulation being effected with upward movement of the piston pump 52 in the manner described. Cam 54 eventually releases the piston of piston pump 52 so that the same moves downwardly thereby releasing the pressure applied to the piston 60 through the fluid traveling in the line 64. This results in an immediate diminishing of the pressure in the line 16 whch is then coupled through the comparatively large conduit or tube 62 with the reservoir 22. The reduction of pressure in the line 16 in turn results in a reduction in pressure in the line 32, and a reduction in pressure in the chamber 30, the result being the immediate initiation of the injectlon phase.

If desired, and for purposes of insuring termination of the injection cycle as desired, the storage means F of FIG- URE 3 can be constructed as shown in FIGURE 6. The arrangement is basically the same as disclosed above, but in this instance an auxiliary biasing spring 76 is incorporated, such spring serving to urge the piston 28 downwardly so that the valve member 14 normally automatically assumes its closed position. Such spring 76 has a lower biasmg force than the spring 8 acting on the piston 6 so that the spring 8 still serves through the piston 6 to apply the injection pressure and control the injection operation.

While FIGURE 3 meters the fuel supplied to the storage means S through utilization of the piston pump 52 and its associated components, the metered quantity can be va- 9 ried. For example, a control element 66 of conventional type can be associated therewith so as to position the tapered face 65 of the piston pump 52 in a selected lowermost position. A different form of metering can equally effectively be achieved with the systems of FIGURES 1 and 2. Specifically, the chamber expansion means of the storage means S of FIGURES 1 and 2 can be modified.

Consider initially FIGURE 4. Here, the metering means includes the piston 6, the spring 8 and the frame or housing 811, as in FIGURE 1. Additionally a stop adjustment means is incorporated. The stop adjustment means comprises a screw 70 threadably received in the rear wall 68 of the frame 8a. The forward end 70a of the screw 70 limits outward movement of the piston 6 thereby limiting the quantity of fuel which can be introduced into the chamber 4 and specifically branch 4:: thereof during a charging or accumulation operation of the storage means S. With the movement of the piston 6 being controlled outwardly by the screw 70, and with the movement of the piston 6 being controlled inwardly by engagement of the piston head 6a with the forward wall 69 of the frame means 8a, the quantity of fluid expelled from the chamber 4 through the injection tube 12 can be closely controlled.

A modified metering arrangement is presented in FIG- URE 5. Here, the frame means takes the form of a closed housing 71 with the screw 70 threadably received in the rear wall thereof. The housing communicates through an outlet line 74 with the fuel supply reservoir 22. The piston, designated as 6' in this instance, is centrally recessed and carries a ball valve 70' therein. The ball valve has a plunger stem 72 leading rearwardly thereof. The ball valve 70' normally seats on the wall 6b of the recess making the piston 6' essentially a closed piston like the pistons 6 described above. When, however, the piston 6 is displaced to the left as shown in FIGURE 5, the valve stem 72 engages the forward end 70a of the screw 70 and the ball valve 70' is unseated. At such time, the piston 6 becomes an open piston and fuel flows therethrough into the chamber 73 in the housing 71 and from there through the line 74 to the fuel supply reservoir 22. Still, the ball valve 70 is not unseated until the piston 6' has moved to its outermost position. Thus, a selected metered quantity of fuel is introduced into the branch 40 before the valve 70 is unseated. This quantity remains constant and is adjusted by adjustment of the screw 70. When the metering means of FIGURE is associated with a storage means S such as shown in the other figures, and when the valve member 14 moves upwardly at the beginning of the injection phase, the piston 6 moves inwardly with the ball valve 70' again seating itself on the wall 6b. The piston 6' then operates in the same manner as the piston 6 causing the expulsion of a metered quantity of fluid from the associated storage means S, the quantity being limited by the inward movement of the piston 6' as controlled by the engagement of the head 6'a with the forward wall of the chamber 73.

Aithough the various storage chamber means discussed above have practical utility in their own right, the preferred form of storage chamber means used in accordance with the invention is constructed as shown in FIGURE 7. This storage chamber means has many features which are common with the features of the storage chamber means described above, but some differing structural aspects affording significant advantages.

Corresponding to the embodiments discussed above, the arrangement of FIGURE 7 includes a hydraulically responsive outlet or control valve means including the piston member 28", a one-way valve means 26" for selectively permitting fuel fiow into the storage chamber means, and a metering means including the piston 6". These various means are coaxially disposed in the arrangement of FIGURE 7, yet operate in essentially the same manner as that described in connection with corresponding means of other figures.

The storage chamber housing of FIGURE 7 includes essentially three sections, namely, a central section 78, a lower section 89, and an upper section 73. The lower section includes a threaded upper portion 80a which is threadably received in a threaded bore 78a at the lower end of the central section 78. The upper section 73 includes a sleeve 73a, having its lower end sealingly engaged with the upper face 781) of the central section 73. To this end a sealing gasket 780 is disposed in a recess 78d in face 78b, and recess 73d receives a lower end flange portion on the sleeve 73a. A cover member 732 is sealingly received on the upper end of the sleeve 73a and fixed in position by means of longitudinally extending bolts 73 The sealing arrangement 73g is the same as the sealing arrangement associated with the sealing gasket 78c, and further description thereof appears unnecessary.

The lower section 80 is centrally bored or hollow and provides a piston chamber for the piston 28" and an outlet chamber 104 receiving valve means 14". The valve means 14 takes the form of a projecting lower end stem on piston 28"; which stern normally blocks the injection passageway or nozzle 12.". The stem forming valve means 14" is of smaller diameter than the interior diameter of the section 80 so that a chamber 104 is formed interiorly of the lower end of the section 80 and about the stem or valve means 14".

Extending upwardly from the piston 28" is a hollow stem or rod 86 having a longitudinally extending bore or passageway 88 therein. The stem 86 passes axially into, and partially through, the central section 78 of the housing. Slidably received thereon are a pair of valve ele ments 26"a and 26"b. The central section 78 of the housing has a shoulder 90 formed toward the lower end thereof which shoulder norrnally receives the base of the valve element 26"a in sealing contact therewith. On the other hand, the valve element 26!) carries at its lower end a tapered ring flange 96 which normally seats on the spherically tapered upper face 94 of the valve element 26"a. The valve element 26"b is biased such that the flange 96 thereof normally bears in sealing relation on the surface 94, such biasing resulting from the provision of a spring means 98 compressible between the upper end of the valve element 26"b and a transverse partition 98a disposed interiorly and across the hollow portion of the central section 78. As should be apparent, the shoulder 90 and the partition 98a serve to define there between a chamber 78a in the central section 78, which chamber has the valve elements 26"a and 26"b therein.

The partition 98a is maintained in the position shown not only by the spring 98, but also by a sleeve 82 which is threadably received in the upper portion of the central section 78. The sleeve 82 has its lower edge 82a disposed to prevent upward movement of the partition 98a. Moreover, the sleeve 82 is provided with a central bore which slidably receives the piston 6". This piston corresponds in construction to the piston 6' shown in FIGURE 5. The piston is recessed and carries therein a valve member 70" which operates in the same manner as the ball valve member 70 described in connection with FIGURE 5. The piston 6 is normally biasted downwardly by a bearing block 84 which itself is urged downwardly by biasing spring means 8".

The specific details of construction of the piston 6 and of the valve member 70 associated therewith have been described above in connection with FIGURE 5, the arrangement of FIGURE 7 in this regard being the same as that shown in FIGURE 5. Certain passageways are provided in the arrangement of FIGURE 7 to cooperate with the valve means 70", and similarly, certain other passageways are incorporated to provide for fuel introduction and flow in association with the other valve means 28 and 26 of FIGURE 7. These passageways and the functionsperformed thereby can be better under- 1 I stood from the operation of the embodiment of FIGURE 7 now to be described.

With the coaxial arrangement of FIGURE 7, fuel under pressure is fed into the system through the line 16, and such fuel passes through the longitudinally extending passageway formed by the bore 100 and through the lateral passageway formed by the bore 32. The fuel enters a chamber 33" above the piston 28" and then passes upwardly about the stem 86 into a recess chamber 102 in the valve element 26"a. When under pressure, such fuel maintains the piston 28" in its downward position thus in turn maintaining the valve means 14" in blocking or closing relation to the injection tube or nozzle 12". Still, the fuel under pressure exerts suflicient force on the valve element 26"b to cause the same to move upwardly against the action of the spring 98. This breaks the seal between the flange 96 and the surface 94 thereby permitting the fluid to flow into the chamber 78a. The fluid then travels through such chamber and through apertures in the partition 98a into the chamber 4" above the partition. The piston 6" communicates or faces this chamber 4". When the fuel reaches the chamber 4", it passes into the lateral openings 106 in the valve stem 86 and then flows downwardly through the passageway 88 and into the chamber 104 through the lateral passageways 108 in the stem forming valve means 14".

Once the fuel has filled the various chambers described, then when additional fluid is sent through the line 16 into the arrangement of FIGURE 7, the same causes the piston 6" to move upwardly thereby expanding the chamber 4". Upward movement of the piston 6" continues until the valve means 70 opens whereupon additional fuel supply passes through the valve means 70 in the piston 6" and then laterally outward through the passageways 70"b and 84a into the chamber formed by the sleeve 73. This escaping fuel is returned to the supply by the line 74 which communicates with the interior of the sleeve 73 through the bores 74a and 74b in the central section 7 8 of the housing.

Consistent with the above, a metered quantity of fuel is accumulated in the storage means. Such quantity of fuel is injected into a cylinder associated with the storage means during the injection phase. Here again, the injection is initiated when the pressure in the line 16 is diminished.

Specifically, with the relief in pressure on the fuel in the line 16, the pressure is relieved on the fuel in the bore 100, in the bore 32" and in the chamber 33". Similarly, the pressure is relieved on the fuel in the recess chamber 102 of the valve element 26"a. Such reduction in pressure effects two results, namely, the valve element 26"b immediately returns to a position where the ring flange 96 is in sealing engagement with the surface 94, and the piston 28" moves upwardly, the piston 6" having been previously moved upwardly during the fuel accumulation period. Pressure is still maintained on the fuel in the chamber 4", in the passageway 88, and in the chamber 104, so the fuel is injected through the injection tube or nozzle 12" until such time as the piston 6" returns to its initial position. At this time, the piston 28' has returned to its initial position, and the arrangement is ready to again be charged with a metered quantity of fuel just as described above.

The concentric arrangement of the various moving elements permits one to obtain precision in operation without extreme precision in construction of the moving parts and associated elements. A simple machine finish is sufficient to prevent fluid leaks within the arrangement. The provision of the tapered ring flange on the valve element 26"b in cooperation with the spherically tapered surface 94 on the valve element 26"a permits these cooperating valve parts to adjust themselves for a proper seal therebetween.

The concentric disposition of the elements of FIG- URE 7 serves to yield not only efiicient operation without requiring extreme precision in the parts, but also permits the use of longitudinally and laterally extending bores in the housing of the storage means. This latter feature affords substantial advantage from the construction standpoint over presently available control valve systems which require oblique bores and passageways. It is important to note with respect to FIGURE 7:

(1) that at the very moment that the cyclic decline of the fuel supply pressure is produced, the decline in pressure which is the signal for initiating the injection, the pressure falls within chamber 33 so that simultaneously one-way valve 26" is closed and piston 28 is lifted by the reverse pressure differential upon its two faces; and

(2) that the metered quantity of fuel accumulated is completely injected within the engine cylinder under the action of piston 6", and at the end of its stroke, piston 6" comes to rest on stem 86 thereby maintaining valve stem 14" over bore 12 of the injection nozzle. Upon recovering essentially the initial position, all of the chambers and passageways within the system remain completely filled with fuel.

As previously indicated, any of the arrangements and systems described above can be used with multi-cylinder internal combustion engines, even though in the preceding descriptions a single cylinder has been used in each instance for a basis of explanation of the various embodiments. Regardless of the particular embodiment employed, the general arrangment is as shown in FIGURE 8.

By referring to FIGURE 8, it will be noted that the overall system includes a plurality of storage chamber means S and a plurality of hydraulically responsive control means C. Each control means C couples one of the storage chambers S with one of the cylinders 2. Each control means C is operative to establish and disestablish communication between the storage chamber means S and the cylinder 2 coupled together thereby.

Hydraulic circuit means CR are coupled with each of the control means for respectively applying fluid under pressure thereby to diestablish communication between the storage chamber 2 coupled together thereby during at least a part of the noninjection thereof and for diminishing the pressure applied to the respective control means C during the injection phase of the cylinder 2 coupled therewith.

The detailed construction of each control means C, storage chamber means S, and hydraulic circuit means CR will vary with the particular embodiment. For example, if the embodiment of FIGURE 1 is used, the input lines 1 will receive fuel from a given source, and the input lines I will receive hydraulic fluid of suitable type, from a separate source. With the embodiment of FIGURE 3, the input lines 1 and 7" would both receive fuel. Still, it should be appreciated readily that regardless of the embodiment utilized, the basic arrangement, and basic function of the respective means corresponds to the general arrangement of FIGURE 8.

Having now described illustrative and preferred embodiments of the invention in considerable detail, it should be apparent that the objects set forth at the outset of the present specifications have been fully satisfied. It should further be apparent that various modifications can be made to the particular embodiments described without departing from the scope and spirit of the invention. Accordingly,

What is claimed is:

1. Injection apparatus for use with an internal combustion engine having a plurality of cylinders, said apparatus comprising:

a plurality of storage chamber means;

a plurality of hydraulically responsive control means, each of said control means coupling one of said storage chamber means with one of said cylinders, each of said control means being operative to establish and disestablish communication between the storage chamber means and the cylinder coupled together thereby;

hydraulic circuit means coupled with each of said control means for respectively applying fluid un der pressure thereto to disestablish communication between the storage chamber means and the cylinder coupled together thereby during at least a part of the non-injection phase thereof and for diminishing the pressure applied to the respective control means during the injection phase of the cylinder coupled therewith;

each of said storage chamber means including a common housing having a main chamber and a branch chamber communicating therewith;

said control means being movably mounted only in said main chambers;

a piston movable in said branch chamber to vary the capacity thereof; and

biasing means for normally urging said .piston in a direction minimizing the capacity of said branch chamber.

2. Injection apparatus as defined in claim 1 wherein each of said storage chamber means further includes means for metering a predetermined quantity of fuel stored therein.

3. Injection apparatus as defined in claim 2 wherein said means for metering includes an adjustable screw which can be variably positioned to act as a stop for limiting movement of said piston against the urging effect of said biasing means.

4. Injection apparatus as defined in claim 1 further including said housing having an injection outlet; said control means comprising piston operated valve means normally closing said injection outlet, said housing having a fuel inlet and a non-return valve means disposed in said housing in the fluid path between said inlet and said main chamber, said main chamber communicating interiorly of said housing with said injection outlet, said non-return valve means comprising a pair of valve elements, at least one of which is reciprocally movable with the other, said piston means, said piston operated valve means and said non-return valve means being coaxially disposed.

5. Injection apparatus as defined in claim 4 wherein said piston operated valve means includes a piston stem extending axially of said housing and having a passageway therethrough communicating said main chamber with said injection outlet, and wherein said valve elements are slidably received about said stem.

6. Injection apparatus as defined in claim 5 wherein said valve elements have mating surfaces respectively of ring shape and spherical contour adapted to form a fluid seal there-between, the element having the spherical mating surface contour also having an opposed planar face, said housing having a planar abutment therein mating with said planar face.

7. Injection aparatus as defined in claim 4 wherein said storage chamber means includes metering means having at least one movable element coaxially disposed with said piston means, said piston operated valve means and said non-return valve means.

8. Injection apparatus as defined in claim 7 wherein said metering means includes a valve member carried by said piston means.

9. In a fuel injection apparatus for use with an internal combustion engine having cylinders therein, the combination comprising:

storage chamber means coupled to said cylinders;

hydraulically operable control means in each of said storage means;

each of said control means being movable between a first position which disestablishes communication between a cylinder and its associated storage chamber means and a second position which establishes such communication;

hydraulic circuit means adapted to be connected to a fuel supply source for delivering fuel therefrom to said storage chamber means;

fuel pump means in said hydraulic circuit to selectively deliver said fuel from said supply source to said storage chamber means; release valve means in said hydraulic circuit connected respectively between said fuel pump means, said fuel supply source and said storage chamber means;

said release valve means being maintained in a first position by pump pressure while said fuel pump means delivers fuel from said supply source to said storage chamber means;

said control means being maintained in their first position while said release valve means is maintained in its first position by the pressure of the fuel delivered to said storage chamber means;

said release valve means moving from said first position to a second position when said fuel pump means terminates fuel delivery and decreases pump pressure upon said release valve means, thereby creating a reduction of pressure in said hydraulic circuit means;

said reduction in pressure in said hydraulic circuit means thereby permitting said control means to move from said first position to said second position to thereby establish communication between said storage chamber means and said cylinders to thus initiate injection of the fuel from said storage chamber means into said cylinders.

10. The combination defined in claim 9 wherein said hydraulic circuit means includes a line extending from said fuel pump means to said release valve means, and a valve in said line permitting flow from said pump means to said release valve means but preventing back flow therefrom.

11. The combination defined in claim 9 wherein said control means and said release valve means each include a piston having a valve stem projecting therefrom and adapted to mate with an associated valve seat.

12. The combination defined in claim 9 wherein said control means includes a pair of spaced pressure receiving faces, one disposed nearer said cylinder and one disposed further away therefrom, said hydraulic circuit means including a line extending from said release valve means to said storage chamber means and connecting adjacent sair nearer face, an auxiliary line branching from said line to said storage chamber means and connecting adjacent said further face, and a valve in said line permitting flow into said storage chamber means but preventing backfiow therefrom.

References Cited by the Examiner UNITED STATES PATENTS 1,585,277 5/1926 Bell 123-32 1,850,250 3/1932 Von Salis 123-43915 2,191,186 2/1940 Amery 123 139.15 2,347,363 4/1944 Palum-bo 123-13915 2,556,356 6/1951 Alfaro et al 239-96 FOREIGN PATENTS 526,723 3/1939 Great Britain.

MARK NEWMAN, Primary Examiner. RICHARD B. WILKINSON, Examiner. 

1. INJECTION APPARATUS FOR USE WITH AN INTERNAL COMBUSTION ENGINE HAVING A PLURALITY OF CYLINDERS, SAID APPARATUS COMPRISING: A PLURALITY OF STORAGE CHAMBER MEANS; A PLURALTIY OF HYDRAULICALLY RESPONSIVE CONTROL MEANS, EACH OF SAID CONTROL MEANS COUPLING ONE OF SAID STORAGE CHAMBER MEANS WITH ONE OF SAID CYLINDERS, EACH OF SAID CONTROL MEANS BEING OPERATIVE TO ESTABLISH AND DISTABLISH COMMUNICATION BETWEEN THE STORAGE CHAMBER MEANS AND THE CYLINDER COUPLED TOGETHER THEREBY; HYDRAULIC CIRCUIT MEANS COUPLED WITH EACH OF SAID CONTROL MEANS FOR RESPECTIVELY APPLYING FLUID UNDER PRESSURE THERETO TO DISESTABLISH COMMUNICATION BETWEEN THE STORAGE CHAMBER MEANS AND THE CYLINDER COUPLED TOGETHER THEREBY DURING AT LEAST A PART OF THE NON-INJECTION PHASE THEREOF AND FOR DIMINISHING THE PRESSURE APPLIED TO THE RESPECTIVE CONTROL MEANS DURING THE INJECTION PHASE OF THE CYLINDER COUPLED THEREWITH; EACH OF SAID STORAGE CHAMBER MEANS INCLUDING A COMMON HOUSING HAVING A MAIN CHAMBER AND A BRANCH CHAMBER COMMUNICATING THEREWITH; SAID CONTROL MEANS BEING MOVABLY MOUNTED ONLY IN SAID MAIN CHAMBERS; A PISTON MOVABLE IN SAID BRANCH CHAMBER TO VARY THE CAPACITY THEREOF; AND BIASING MEANS FOR NORMALLY URGING SAID PISTON IN A DIRECTION MINIMIZING THE CAPACITY OF SAID BRANCH CHAMBER. 